Abstract
In the development of diabetic nephropathy, pathological damage such as interstitial fibrosis and cell apoptosis often occur in renal tubules. In the present study, diabetic and control group mice were randomly treated with vitamin D3 or vehicle for 6 months. In addition, human renal tubular epithelial (HK-2) cells were cultured in high-glucose medium and treated with vitamin D3 or the oxidative inhibitor NAC. Immunohistochemistry, western blotting, quantitative PCR), and ELISA showed that vitamin D3 decreased the expression of α-smooth muscle actin and E-cadherin in renal tubular epithelial cells, improving interstitial fibrosis. It also downregulated the ratio of Bax/Bcl2 protein, alleviating apoptosis in renal tubular epithelial cells. Furthermore, vitamin D3 significantly inhibited oxidative stress response in renal tubular epithelial cells and blocked the (Thioredoxin Interacting Protein) TXNIP/NLRP3 inflammatory pathway. Therefore, vitamin D3 can protect renal tubular epithelial cells from fibrosis and apoptosis by inhibiting oxidative stress response and blocking the TXNIP/NLRP3 inflammatory pathway in diabetic nephropathy.